Organic light-emitting diodes (OLEDs) utilize a layer of organic luminescent material that, when sandwiched between electrodes and subjected to a DC electric current, produces light of a variety of colors (wavelengths). These OLED structures can be combined into picture elements or “pixels” to form an OLED display. OLEDs are also useful in a variety of applications as discrete light-emitting devices or as the active element of light-emitting arrays or displays, such as flat-panel displays in watches, telephones, laptop computers, pagers, cellular phones, calculators, and the like. To date, the use of OLEDS to form light-emitting arrays or displays has been largely limited to small-screen applications such as those mentioned above.
Demands for large-format displays having higher quality and higher resolution have led the industry to turn to alternative display technologies to replace older LED and liquid crystal displays (LCDs). For example, LCDs fail to provide the bright, high light output, larger viewing angles, and high resolution and speed requirements that the large-format display market demands. Another drawback of conventional LCD's is the fact that the driving interconnections are made from the sides, which precludes efficient tiling of LCD-based display modules. By contrast, OLEDs promise bright, vivid colors in high resolution and at wider viewing angles and so are an appealing option as light sources for large-format displays, such as outdoor or indoor stadium displays, large marketing advertisement displays, and mass-public informational displays.
To date, the use of OLED technology in large-format displays has largely relied upon the same technology used for smaller OLED displays. While this approach is simple and generally sensible, it can also be relatively expensive and not always optimal for the given application.